The present invention relates to an apparatus for an electric power tool provided with an overload protection function that serves to detect, when a battery discharges, an overload state of the battery and interrupts a discharge path.
An apparatus for an electric power tool provided with such overload protection function has a problem that: when the battery has reached the overload state during use of the electric power tool, a discharge path from the battery is interrupted and operation of the electric power tool is stopped without any advance notice to a user of the electric power tool.
In order to address the problem, an example apparatus for an electric power tool disclosed, for example, in Japanese Unexamined Patent Application Publication No. 2004-173471 is configured to include a shunt resistor for detecting current in the discharge path from the battery to the motor, detect a load level of the motor (and thus of the battery) based on a voltage between both ends of the shunt resistor, and indicate the load level using a plurality of indicator elements.